1. Field of the Invention
The present invention relates to a suturing device that is used by being inserted into a body cavity, and more particularly, to a suturing device that is used when suturing a perforation or the like formed in a lumen such as the stomach or the intestine with a suture thread having both ends fixed to an anchor.
2. Description of Related Art
In the past, for the purpose of suture of perforations, lacerations or the like formed in a lumen such as the stomach or the intestine, there has been known a suturing device that uses a suture thread having both ends fixed to an anchor (see WO 2007-37326, for example). In the suturing device, the anchors on both ends of the suture thread are placed to be locked at the tissues around the perforation at the inside or outside of the tissues, and the suture thread is pulled so that the tissues locked at the anchors are tightened up, thereby suturing the tissues.
In the suturing device disclosed in WO 2007-37326, in order to perform the suturing operation in a secure manner, it is necessary to release the anchors fitted to the distal end of the suturing device from the distal end so that only one anchor is released at a time so as to be locked at the opposite tissues around the perforation. For this reason, in the suturing device disclosed in WO 2007-37326, an annular groove is formed on the surface of the anchor so as to be engaged with a protrusion formed on the inner surface of a needle provided on the distal end of the suturing device. When the anchor is released, the groove disengages with the protrusion, which is transferred as a sense of feeling to a user so that the user can perceive the release of the anchor.
However, in the suturing device disclosed in WO 2007-37326, the needle at the distal end and an operating portion that the user operates are connected to a flexible sheath, and the sheath is expanded by the force applied to the released anchor. For this reason, the above-described sense of disengagement generated when the anchor is released is absorbed and attenuated by expansion and shrinkage of the sheath and is not sufficiently transferred to the user.
When the anchor is configured to engage with the needle more tightly in order to sufficiently transfer the sense of disengagement to the user even when the sheath absorbs the disengagement impact, a greater force may be required to release the engagement. As a result, there may be a case in which two anchors are released at a time, making it difficult to perform the suturing operation properly.